1. Field of the Invention
The present invention relates generally to an apparatus and method for frame generation for a full duplex relay in the Institute of Electrical and Electronics Engineers (IEEE) 802.16j system and the IEEE 802.16m system.
2. Description of the Related Art
When a communication network is configured using a conventional design of a cellular mobile communication system, coverage holes may be caused by regional characteristics such as buildings, mountains, tree lines, etc., of the respective regions.
To address these coverage holes, a cellular mobile communication system installs a repeater to provide continuous service in these troubled areas within the cells. However, a repeater may cause performance degradation due to increased noise amplification.
A relay system, which decodes and forwards a signal from a Base Station (BS), instead of simply amplifying the signal, has been proposed as an improvement over the conventional repeater. This type of improved relay system is being extensively researched to provide the coverage extension and throughput enhancement of a cellular mobile communication system. Specifically, the IEEE 802.16j is standardizing a relay system for practical use, wherein in comparison with a conventional single-hop system, the use of the improved relay system improves performance while reducing deployment and maintenance costs.
Relay schemes may generally be classified into two types: (i) a relay scheme performing only one of transmission or reception using one antenna set, and (ii) a relay scheme simultaneously performing transmission and reception using two antenna sets. The former scheme is a half-duplex relay, and the latter scheme is a full duplex relay.
A half-duplex relay may not simultaneously perform transmission and reception in the same frequency band, and performs only one of transmission or reception at a time-by-time division.
Two-time signal transmission for communication between a BS and a Relay Station (RS) and communication between an RS and a Mobile Station (MS) uses twice as much resource consumption than a single-hop system, thus reducing the spectral efficiency and requiring an additional transmit/receive (TX/RX) switching time for relay.
Also, broadcast information for relay is separately transmitted by a BS, and a relay link and an access link are used by time division, which reduces the uplink (UL) coverage of single-hop users served by the BS.
A full duplex relay, which simultaneously performs transmission and reception using two antennas, has been proposed as a scheme for addressing the above limitations. The full duplex relay uses the two antennas to simultaneously communicate with an upper node and a lower node in the same frequency band.
However, it is inefficient to operate the full duplex relay because the current IEEE 802.16j standard is based on the half-duplex relay in spite of the advantages of the full duplex relay.
Also, the full duplex relay may cause an inter-antenna interference because it simultaneously performs transmission and reception using the two antennas, while reusing all the resources.